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[0/2] arm64: dts: qcom: apq8016-sbc-d3-camera: Convert to DT overlay

Message ID 20230922-apq8016-sbc-camera-dtso-v1-0-ce9451895ca1@gerhold.net (mailing list archive)
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Series arm64: dts: qcom: apq8016-sbc-d3-camera: Convert to DT overlay | expand

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Stephan Gerhold Sept. 22, 2023, 3:11 p.m. UTC
Follow the example of the recently added apq8016-sbc-usb-host.dtso and 
convert apq8016-sbc-d3-camera-mezzanine.dts to a DT overlay that can be 
applied on top of the apq8016-sbc.dtb. This makes it more clear that 
this is not a special type of DB410c but just an addon board that can 
be added on top.

I also prepended a patch that cleans up the node names a bit.

Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
---
Stephan Gerhold (2):
      arm64: dts: qcom: apq8016-sbc-d3-camera: Use more generic node names
      arm64: dts: qcom: apq8016-sbc-d3-camera: Convert to DT overlay

 arch/arm64/boot/dts/qcom/Makefile                    |  5 +++--
 ...nine.dts => apq8016-sbc-d3-camera-mezzanine.dtso} | 20 ++++++++++++++------
 2 files changed, 17 insertions(+), 8 deletions(-)
---
base-commit: 7236e86ce5c8198b01c30933c2334d07d877cf48
change-id: 20230922-apq8016-sbc-camera-dtso-f247bea40f99

Best regards,

Comments

Bryan O'Donoghue Sept. 22, 2023, 8:47 p.m. UTC | #1
On 22/09/2023 16:11, Stephan Gerhold wrote:
> Follow the example of the recently added apq8016-sbc-usb-host.dtso and
> convert apq8016-sbc-d3-camera-mezzanine.dts to a DT overlay that can be
> applied on top of the apq8016-sbc.dtb. This makes it more clear that
> this is not a special type of DB410c but just an addon board that can
> be added on top.
> 
> I also prepended a patch that cleans up the node names a bit.
> 
> Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
> ---
> Stephan Gerhold (2):
>        arm64: dts: qcom: apq8016-sbc-d3-camera: Use more generic node names
>        arm64: dts: qcom: apq8016-sbc-d3-camera: Convert to DT overlay
> 
>   arch/arm64/boot/dts/qcom/Makefile                    |  5 +++--
>   ...nine.dts => apq8016-sbc-d3-camera-mezzanine.dtso} | 20 ++++++++++++++------
>   2 files changed, 17 insertions(+), 8 deletions(-)
> ---
> base-commit: 7236e86ce5c8198b01c30933c2334d07d877cf48
> change-id: 20230922-apq8016-sbc-camera-dtso-f247bea40f99
> 
> Best regards,

db410c doesn't ship with a bootloader that is capable of applying a dtbo 
though, so this conversion mandates an updated or chainloaded bootloader 
or out-of-tree kernel patch to support.

__adding__ is fine but, converting implies imposes a new requirement on 
the bootchain.

Perhaps a middle road solution is to

- Add, not convert a standalone dtbo or
- Add a dtbo that includes the mezzanine dts but amends it

Option 2 for preference but, I'm not sure the dts syntax can be 
meaningfully made to do that.

---
bod
Stephan Gerhold Sept. 22, 2023, 8:58 p.m. UTC | #2
On Fri, Sep 22, 2023 at 09:47:07PM +0100, Bryan O'Donoghue wrote:
> On 22/09/2023 16:11, Stephan Gerhold wrote:
> > Follow the example of the recently added apq8016-sbc-usb-host.dtso and
> > convert apq8016-sbc-d3-camera-mezzanine.dts to a DT overlay that can be
> > applied on top of the apq8016-sbc.dtb. This makes it more clear that
> > this is not a special type of DB410c but just an addon board that can
> > be added on top.
> > 
> > I also prepended a patch that cleans up the node names a bit.
> > 
> > Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
> > ---
> > Stephan Gerhold (2):
> >        arm64: dts: qcom: apq8016-sbc-d3-camera: Use more generic node names
> >        arm64: dts: qcom: apq8016-sbc-d3-camera: Convert to DT overlay
> > 
> >   arch/arm64/boot/dts/qcom/Makefile                    |  5 +++--
> >   ...nine.dts => apq8016-sbc-d3-camera-mezzanine.dtso} | 20 ++++++++++++++------
> >   2 files changed, 17 insertions(+), 8 deletions(-)
> > ---
> > base-commit: 7236e86ce5c8198b01c30933c2334d07d877cf48
> > change-id: 20230922-apq8016-sbc-camera-dtso-f247bea40f99
> > 
> > Best regards,
> 
> db410c doesn't ship with a bootloader that is capable of applying a dtbo
> though, so this conversion mandates an updated or chainloaded bootloader or
> out-of-tree kernel patch to support.
> 
> __adding__ is fine but, converting implies imposes a new requirement on the
> bootchain.
> 
> Perhaps a middle road solution is to
> 
> - Add, not convert a standalone dtbo or
> - Add a dtbo that includes the mezzanine dts but amends it
> 
> Option 2 for preference but, I'm not sure the dts syntax can be meaningfully
> made to do that.
> 

With these patches the apq8016-sbc-d3-camera-mezzanine.dtb is still
magically built, by running fdtoverlay on apq8016-sbc.dtb and applying
the dtbo. It's applied during the build process so you don't need a
bootloader that supports DTBOs.

There is literally *no change* for you in terms of usage. :-)

Thanks,
Stephan
Bryan O'Donoghue Sept. 22, 2023, 9:13 p.m. UTC | #3
On 22/09/2023 21:58, Stephan Gerhold wrote:
> On Fri, Sep 22, 2023 at 09:47:07PM +0100, Bryan O'Donoghue wrote:
>> On 22/09/2023 16:11, Stephan Gerhold wrote:
>>> Follow the example of the recently added apq8016-sbc-usb-host.dtso and
>>> convert apq8016-sbc-d3-camera-mezzanine.dts to a DT overlay that can be
>>> applied on top of the apq8016-sbc.dtb. This makes it more clear that
>>> this is not a special type of DB410c but just an addon board that can
>>> be added on top.
>>>
>>> I also prepended a patch that cleans up the node names a bit.
>>>
>>> Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
>>> ---
>>> Stephan Gerhold (2):
>>>         arm64: dts: qcom: apq8016-sbc-d3-camera: Use more generic node names
>>>         arm64: dts: qcom: apq8016-sbc-d3-camera: Convert to DT overlay
>>>
>>>    arch/arm64/boot/dts/qcom/Makefile                    |  5 +++--
>>>    ...nine.dts => apq8016-sbc-d3-camera-mezzanine.dtso} | 20 ++++++++++++++------
>>>    2 files changed, 17 insertions(+), 8 deletions(-)
>>> ---
>>> base-commit: 7236e86ce5c8198b01c30933c2334d07d877cf48
>>> change-id: 20230922-apq8016-sbc-camera-dtso-f247bea40f99
>>>
>>> Best regards,
>>
>> db410c doesn't ship with a bootloader that is capable of applying a dtbo
>> though, so this conversion mandates an updated or chainloaded bootloader or
>> out-of-tree kernel patch to support.
>>
>> __adding__ is fine but, converting implies imposes a new requirement on the
>> bootchain.
>>
>> Perhaps a middle road solution is to
>>
>> - Add, not convert a standalone dtbo or
>> - Add a dtbo that includes the mezzanine dts but amends it
>>
>> Option 2 for preference but, I'm not sure the dts syntax can be meaningfully
>> made to do that.
>>
> 
> With these patches the apq8016-sbc-d3-camera-mezzanine.dtb is still
> magically built, by running fdtoverlay on apq8016-sbc.dtb and applying
> the dtbo. It's applied during the build process so you don't need a
> bootloader that supports DTBOs.
> 
> There is literally *no change* for you in terms of usage. :-)

Ah I see

+apq8016-sbc-d3-camera-mezzanine-dtbs	:= apq8016-sbc.dtb 
apq8016-sbc-d3-camera-mezzanine.dtbo

I guess I like the idea of having the base board dtb a mezzanine.dtb and 
a dtbo that could be applied as an overlay to the base board dtb, 
optionally.

Our model then for mezzanine enablement wouild be

1. baseboard.dtb
2. baseboard-mezzanine.dtb
3. baseboard-mezzanine.dtbo

With booting #2 or #1+#3 resulting in the same image but, potentially 
allowing for

1. baseboard.dtb
2. baseboard-mezzanine.dtb
3. baseboard-mezzanine.dtbo
4. baseboard-some-other-mezzanine.dtb
5. baseboard-some-other-mezzanine.dtbo

#1 + #3 + #5 which would represent a hypothetical stacking of mezzanine 
boards.

As a model, I think that has merit.

Reviewed-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Bjorn Andersson Jan. 28, 2024, 5:45 p.m. UTC | #4
On Fri, 22 Sep 2023 17:11:55 +0200, Stephan Gerhold wrote:
> Follow the example of the recently added apq8016-sbc-usb-host.dtso and
> convert apq8016-sbc-d3-camera-mezzanine.dts to a DT overlay that can be
> applied on top of the apq8016-sbc.dtb. This makes it more clear that
> this is not a special type of DB410c but just an addon board that can
> be added on top.
> 
> I also prepended a patch that cleans up the node names a bit.
> 
> [...]

Applied, thanks!

[1/2] arm64: dts: qcom: apq8016-sbc-d3-camera: Use more generic node names
      commit: 0f893a2cb1ab7af6c88cfa1034debb6a790fb6c6
[2/2] arm64: dts: qcom: apq8016-sbc-d3-camera: Convert to DT overlay
      commit: ea689ec32bf0d885277d3f58450a85df5149c98b

Best regards,